Apparatus for controlling the lateral position of an elongated web

ABSTRACT

This apparatus includes means for changing the length of the path of one edge of a longitudinally moving web in comparison to the length of the path of the other edge. The path lengths are changed in order to shift the web laterally with respect to its path of movement, so as to maintain the web within a predetermined range of deviation from a central position. The apparatus includes an edge sensing means for each edge of the web, and a pair of motors, each controlled by one edge sensing means and operating a device which changes the length of the path for one edge of the web. The device which changes the path length comprises a pair of fixed parallel bars or rollers defining a straight path for one run of the moving web, and a movable bar normally spaced from but movable to engage the web between the two fixed bars and having its end movable by the two motors. The movable bar is convex in the direction of web movement and may also be convex in the direction perpendicular to the direction of web movement. The apparatus is shown as used in connection with a wiping web for an intaglio printing press. The web moves between the plate cylinder of the press and a wiping shoe. The apparatus may be double acting, i.e., each motor may operate one path length changing means upstream from the pad over which the web moves and another path length changing means downstream from that pad.

United States Patent [191 DAmato et al.

[4 1 May 6,1975

[ APPARATUS FOR CONTROLLING THE LATERAL POSITION OF AN ELONGATED WEB[75] Inventors: Salvatore F. DAmato, Floral Park;

Chauncey P. Foote, Jr., Katonah, both of NY.

[73] Assignee: American Bank Note Company,

New York, NY.

[22] Filed: Aug. 20, 1973 [21] Appl. No.: 390,001

Primary ExaminerRichard A. Schacher Attorney, Agent, or FirmCooper,Dunham, Clark, Griffin & Moran [57] ABSTRACT This apparatus includesmeans for changing the length of the path of one edge of alongitudinally moving web in comparison to the length of the path of theother edge. The path lengths are changed in order to shift the weblaterally with respect to its path of movement, so as to maintain theweb within a predetermined range of deviation from a central position.The apparatus includes an edge sensing means for each edge of the web,and a pair of motors, each controlled by one edge sensing means andoperating a device which changes the length of the path for one edge ofthe web. The device which changes the path length comprises a pair offixed parallel bars or rollers defining a straight path for one run ofthe moving web, and a movable bar normally spaced from but movable toengage the web between the two fixed bars and having its end movable bythe two motors. The movable bar is convex in the direction of webmovement and may also be convex in the direction perpendicular to thedirection of web movement. The apparatus is shown as used in connectionwith a wiping web for an intaglio printing press. The web moves betweenthe plate cylinder of the press and a wiping shoe. The apparatus may bedouble acting, i.e., each motor may operate one path length changingmeans upstream from the pad over which the web moves and another pathlength changing means downstream from that pad.

4 Claims, 5 Drawing Figures PATENTED HAY 6 I975 SHEET 10F 2 APPARATUSFOR CONTROLLING THE LATERAL POSITION OF AN ELONGATED WEBCROSS-REFERENCES US. Pat. application, Ser. No. 298,443, filed Oct. 17,1972, by Ivaldo Gazzola et al; and entitled PRINTING PRESSURE CONTROLAPPARATUS FOR INTA- GLIO PRESS, discloses a press similar to thatillustrated herein and with which the present invention will be used.

US. Pat. application, Ser. No. 372,066, filed June 21, 1973, by thepresent inventors, entitled INTA- GLIO PRINTING PRESS WITH WEB WIPINGAP- PARATUS HAVING SUPPLY AND TAKE-UP REELS OUTSIDE FRAME, discloses apress having a web wiping apparatus with which the present invention maybe used. 1

BRIEF SUMMARY OF THE INVENTION In any apparatus employing an elongatedweb of indefinite length, it is necessary to supply some means formaintaining the web in correct lateral alignment with regard to itssupply and take-up reels and the intermediate guiding members over whichit runs. It has been proposed to guide the moving web, i.e., to shiftthe moving web laterally, by changing the length of the path traveled byone edge of the web as compared to the length of the path traveled bythe opposite edge. For example, the US. Pat. to Medkeff, No. 2,814,487,shows an apparatus in which the distances traveled by the two edges ofthe web are varied by pivoting the supply roll about an axisperpendicular to the axis about which it rotates to deliver the webmaterial.

I-Iimrod et al; US. Pat. No. 3,317,101 suggests the use of a camberingroll which is variably tilted with respect to the direction of motion ofthe web for the purpose of shifting the web laterally.

Kurz, US. Pat. No. 3,570,735 shows a pair of rolls engaging oppositesides of a web and suggests a shifting of those rolls in some fashionnot clearly explained, for influencing the lateral movement of the web.

The present invention maintains the web in a central position morestably and without overcontrolling the lateral movement of the web. Inthe present invention, two edge sensing devices are used, one at eachedge of the web, and each edge sensing device controls a motor whichchanges the distance moved by one edge of the web.

The mechanism for changing the distances moved by edges of the webcomprises a non-rotating bar engaging one face of the web and spacedlongitudinally of the web between two fixed bars or rollers which definea straight path for one rim of the web. Each motor moves one end only ofthe movable bar. In a preferred modification, the movable bar has asurface which is convex both in the longitudinal direction of the weband in the lateral direction of the web.

The distance changing mechanism may operate on the web either upstreamor downstream, or both, from the working station, e.g., the stationwhere the web wipes against the surface of the cylinder of an intagliopress.

DRAWINGS FIG. 1 is a somewhat diagrammatic and partly perspective viewof a web position controlling apparatus embodying the invention.

FIG. 2 is a fragmentary view illustrating a modification.

FIG. 3 is a sectional view, on an enlarged scale, taken on the line 3-3of FIG. 2.

FIG. 4 is a sectional view taken on the line 44 of FIG. 5, illustratinganother modification.

FIG. 5 is a diagrammatic view illustrating a further modification of theinvention.

DETAILED DESCRIPTION FIG. 1

This figure illustrates a plate cylinder 1 for an intaglio press and awiping pad 2 biased into engagement with the surface of the cylinder 1by conventional means not shown, and a wiping web 3 which moves from asupply reel, not shown, along the path of movement indicated by thearrows, between the pad 2 and the cylinder 1 and thence to a take-upreel, also not shown. A pair of edge sensing devices are shown at 4 and5. Each of the devices 4 and 5 comprise a yoke which spans one edge ofthe web 3. The devices 4 and 5 are fiuidic sensors and each has an airinlet connection adapted to be connected through a conduit 6 or 7 to amanifold 8, which receives air from a conduit 11 connected to a supplyof air under pressure. Each of the devices 4 and 5 has an internalpassage 6a or 7a (FIG. 4) connected to its inlet 6 or 7. Each of thepassages 6a and 7a terminates in an opening located on the inside faceof one leg of its yoke. Opposed to those openings 6a, 7a are openings12a, 14a in the opposite leg of the yoke, leading to passages 12a, 14a(FIG. 4) connected to conduits 12 or 14, each communicating with apressure sensitive element generally indicated at 13 or 15 (FIG. 1). Apair of conduits 16 and 17 lead from the manifold 8 to the pressuresensitive elements 15 and 16. Each of the elements l3 and 15 comprises abellows 21 or 22 operating a movable switch contact 23 or 24, connectedto an upper supply line 25 and cooperating with a stationary contact 27or 32, respectively connected to an electromagnet 26 in the case ofswitch contact 23 and an electromagnet 31 in the case of switch contact24. The opposite terminals of the electromagnets 26 and 31 are connectedto a lower supply line 28.

The bellows 21 and 22 are each subject to the difference between thesupply pressure in lines 16 and I7 and the somewhat reduced pressurereceived through the conduits 12 and 14. This pressure difference isbalanced, for normal positions of the web 3, by internal springs withinthe bellows 21 and 22, so that the switches remain open.

The electromagnet 26 operates a piston valve 33 which controls the flowof liquid from a supply line 34 to a hydraulic cylinder 35, and fromcylinder 35 to a low pressure drain line 38. The cylinder 35 operates apiston rod 36 pivotally connected to one arm of a bell crank lever 37.The other arm of lever 37 is connected through a universal joint 41 toone end of a guide bar 42.

Similarly, the electromagnet 31 operates a valve 43 which regulates theflow of hydraulic fluid to and from a hydraulic cylinder 44 connected toone arm of a bell crank lever 45. The other arm of the bell crank lever45 is connected by means of a universal joint 46 to the opposite end ofthe guide bar 42.

The web 3 approaching the wiping shoe 2, normally passes along astraight path over stationary bars 47 and 48. Between those bars, theweb 3 passes under the guide bar 42, which is non-rotating and isnormally spaced from the web 3.

The bars 47 and 48 are mounted in fixed frame members 51 and 52 locatedat the opposite sides of the path of travel of the web 3. The bar 42 ismoved by the cylinders 35 and 44 in a direction which intersects theplane defined by the guide bars 47 and 48. This direction is ideallyperpendicular to that plane, but need not necessarily be perpendicular.In the illustrated embodiment, for example, the direction of movement ofeach end of bar 42 is perpendicular to the plane only in one angularposition of the supporting lever.

OPERATION OF FIG. 1

As long as the lateral position of web 3 remains within a predeterminedrange of a middle position shown in FIG. 4, in which range neithermargin of the web is blocking the flow of air from either port 6a or 7ato the corresponding port 12a or 14a, the switch contacts 23 and 24 aremaintained open, and the valves 33 and 43 are biased by internal springsto their lower position, in which the left ends of the hydrauliccylinders 35 and 44 are connected to hydraulic supply line 34, and theright-hand ends of those cylinders are connected to hydraulic drain line38. Consequently, the bar 42 remains in its normal position spaced abovethe web 3.

The devices 4 and may be adjustably mounted to establish selectively themiddle position just described.

Assume now that the web 3 shifts to the left from the position shown inthe drawing, thus blocking at least partially the flow from the passage6a to the receiving passage 12a. Hence, the bellows 21 contracts andcontact 23 engages the stationary contact 27, energizing theelectromagnet 26 to operate valve 33 to its upper position so that fluidmoves from the supply line 34 through valve 33 to the right-hand end ofcylinder 35, thereby driving the bell crank lever 37 counterclockwiseand lowering the left-hand end of the bar 42 into engagement with theleft edge of web 3. This increases the length of the path of travel ofthe left edge of web 3 as compared to the length of the path of travelof the right-hand end. The web is thereby moved back toward the right,decreasing the blockage of flow between passage 6a and the receivingpassage 12a. This motion continues until contact 23 opens.

If the web 3 shifts to the right from the middle range of positions, theedge sensing device 5 controls the cylinder 44 similarly through thepressure sensitive device and valve 43, so as to move the lever 45counterclockwise and lower the right-hand end of the bar 42, therebyincreasing the length of the path of the righthand edge of the web andmoving the web back toward the left.

The hydraulic supply lines connected to the motors 35 and 44 areprovided with restrictions 53, 54, 55 and 56, which limit the rate offlow of hydraulic fluid into and out of the cylinders 35 and 44, andthereby limit V sensing devices may be operated with their fluid pathsnormally blocked, in which case each sensing device controls thecylinder on the opposite side of the web.

FIGS. 2-3

These figures illustrate a modification of the apparatus shown in FIG.1, in which the straight bar 42 of FIG. 1 is replaced by a bar 61 havinga web engaging surface 61a, which is convex in the direction of webtravel, as seen in FIG. 3, and is also convex in the direction crosswiseof the web, as may be seen in FIG. 2. This conformation of the guide bar61 tends to maintain the web centralized on the bar. Furthermore, if thebar 61 is tilted to one way or the other by the motors 35 or 44, therestoring movement of the web toward the center position is more rapidas compared to the movement with a straight bar 42. This construction ofthe bar is especially desirable in the case of stretchable webs, such ascrinkled kraft paper, which is commonly used for the wiping systems ofintaglio presses.

FIG. 4

This figure illustrates a modification of the apparatus of FIG. 1, inwhich the shoe 2 over which the wiping web runs is oscillated endwise.The shoe 2 is fixed on a shaft 63 for angular movement therewith so thatit may be tilted with respect to the plate cylinder 1, as required bythe particular plate structure and the particular ink to be wipedtherefrom. The shaft 63 carries a double flanged collar 64. Between theflanges of the collar 64 is captured a roller 64 carried by a lever 66,which is oscillated by any suitable conventional means (not shown) asthe plate cylinder 1 rotates. The edge sensing means 4 and 5 in thisfigure are mounted on brackets 67 and 68 fixed on the under side of theshoe 2. The web 3 is thereby made to follow the oscillating lateralmovements of the shoe 2. Such oscillating movements of the shoe arecommon in the art, and are designed to improve the wiping action of theweb against the printing plate. By mounting the sensing devices 4 and 5on the oscillating shoe, the web itself is made to oscillate with theshoe to improve further the wiping action of the web against the plate.

FIG. 5

In this figure, the web 3 moves over the fixed guide bars 47 and 48under a movable guide bar 61 upstream of its path of movement over theshoe 2 and also moves over a pair of fixed guide bars 71 and 72 andunder a movable guide bar 73 located downstream of the path of movementof the web over the shoe 2. The movable guide bar 73 is supported on theend of a lever arm 74 connected by a link 75 to the arm of lever 37which carries the movable guide bar 61. Hence, the lever 37, lever 74,link 75 and the fixed frame of the press constitute a parallelogramlinkage and guide bar 73 follows the movement of the guide bar 61.

By using the mechanism of FIG. 5, the moving web is subjected to alaterally directed position correcting force upstream of the shoe 2 andto another laterally directed position correcting force downstream ofthe shoe 2. The response of the web to the correctional forces isthereby made more rapid, and the web is enabled to follow the lateraloscillations of the shoe 2 more accurately. Furthermore, the correctiveaction is the same, regardless of the direction of movement of the web.

The invention has been described as applied to a wiping web for anintaglio printing press. It will be readily understood by those skilledin the art that the invention has particular utility in connection withsuch a press. Nevertheless, many features of the invention have broaderutility in connection with web transport systems in general. lnparticular, the apparatus of FIG. 5 is useful to control the lateralposition of any web passing through a work station where the web issubjected to longitudinal stress. In the apparatus disclosed, the web 3is subjected to longitudinal stress when it passes the wiping pad 2,since it is being pulled past that pad by the motor driven take-up reel,and the pull of the take-up reel is opposed by the friction between thepad 2 and the cylinder 1.

We claim:

1. A printing press, comprising:

a. wiping means for removing ink from the surface of an inked intaglioplate, comprising: 1. an elongated web movable longitudinally; 2. a padfor holding a portion of the web against the surface of the rotatingcylinder; 3. means for guiding the web between said pad and thecylinder; and 4. means for controlling the lateral position of the web,comprising: i. two edge sensing means; ii. means supporting said twoedge sensing means at the opposite edges of said web; iii. two motors,each controlled by one of said edge sensing means; iv. two fixed guidemeans extending across and engaging the web and spaced longitudinally ofthe web, said two guide means defining a straight run for the web;

v. third guide means extending across and spaced from but movable intoengagement with the web between the two fixed guide means; and

vi. means controlled by each said motor for moving one end of the thirdguide means into engagement with the web so that each motor is effectiveupon operation thereof to change the length of the path traversed by oneedge of the web as compared to the length of the path traversed by theother edge.

2. A printing press as in claim 1, including means on the pad supportingsaid two edge sensing means.

3. A printing press as in claim 1, including:

a. two pairs of fixed guide means, one pair engaging one side of themoving web upstream from the pad and the other pair engaging one side ofthe moving web downstream from the pad;

b. two movable guide means, one operable to engage the web upstream fromthe pad and one operable to engage the web downstream from the pad, eachmovable guide means being operable to engage the web between one pair ofsaid fixed guide means;

c. means operated by each motor to move one end of both the upstream anddownstream movable guide means.

4. A printing press as in claim 1, including:

a. means for oscillating the pad parallel to the axis of the platecylinder; and

b. means on the pad for supporting said edge sensing means.

1. A printing press, comprising: a. wiping means for removing ink from the surface of an inked intaglio plate, comprising:
 1. an elongated web movable longitudinally;
 2. a pad for holding a portion of the web against the surface of the rotating cylinder;
 3. means for guiding the web between said pad and the cylinder; and
 4. means for controlling the lateral position of the web, comprising: i. two edge sensing means; ii. means supporting said two edge sensing means at the opposite edges of said web; iii. two motors, each controlled by one of said edge sensing means; iv. two fixed guide means extending across and engaging the web and spaced longitudinally of the web, said two guide means defining a straight run for the web; v. third guide means extending across and spaced from but movable into engagement with the web between the two fixed guide means; and vi. means controlled by each said motor for moving one end of the third guide means into engagement with the web so that each motor is effective upon operation thereof to change the length of the path traversed by one edge of the web as compared to the length of the path traversed by the other edge.
 2. a pad for holding a portion of the web against the surface of the rotating cylinder;
 2. A printing press as in claim 1, including means on the pad supporting said two edge sensing means.
 3. A printing press as in claim 1, including: a. two pairs of fixed guide means, one pair engaging one side of the moving web upstream from the pad and the other pair engaging one side of the moving web downstream from the pad; b. two movable guide means, one operable to engage the web upstream from the pad and one operable to engage the web downstream from the pad, each movable guide means being operable to engage the web between one pair of said fixed guide means; c. means operated by each motor to move one end of both the upstream and downstream movable guide means.
 3. means for guiding the web between said pad and the cylinder; and
 4. A printing press as in claim 1, including: a. means for oscillating the pad parallel to the axis of the plate cylinder; and b. means on the pad for supporting said edge sensing means.
 4. means for controlling the lateral position of the web, comprising: i. two edge sensing means; ii. means supporting said two edge sensing means at the opposite edges of said web; iii. two motors, each controlled by one of said edge sensing means; iv. two fixed guide means extending across and engaging the web and spaced longitudinally of the web, said two guide means defining a straight run for the web; v. third guide means extending across and spaced from but movable into engagement with the web between the two fixed guide means; and vi. means controlled by each said motor for moving one end of the third guide means into engagement with the web so that each motor is effective upon operation thereof to change the length of the path traversed by one edge of the web as compared to the length of the path traversed by the other edge. 